Role of the cannabinoid signaling in the brain orexin- and ghrelin-induced visceral antinociception in conscious rats

• Published in: Journal of pharmacological sciences Vol. 137; no. 2; pp. 230 - 232
• Main Authors: Okumura, Toshikatsu, Nozu, Tsukasa, Kumei, Shima, Ohhira, Masumi
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 01.06.2018; Elsevier
• Subjects: Analgesics - pharmacology; Analgesics - therapeutic use; Animals; Benzoxazines - pharmacology; Cannabinoid; Cannabinoids - pharmacology; Cannabinoids - therapeutic use; Consciousness - physiology; Ghrelin - pharmacology; Ghrelin - physiology; Male; Morpholines - pharmacology; Naphthalenes - pharmacology; Neuropeptide; Orexins - pharmacology; Orexins - physiology; Rats, Sprague-Dawley; Signal Transduction - physiology; Visceral Pain - drug therapy; Visceral sensation; Cannabinoid; Neuropeptide; Visceral sensation
• ISSN: 1347-8613; 1347-8648
• DOI: 10.1016/j.jphs.2018.06.001

We hypothesized that the cannabinoid (CB) system may mediate the brain orexin- or ghrelin-induced visceral antinociception. Intraperitoneal injection of either CB1/2 agonist, WIN 55212 or O-Arachidonoyl ethanolamine increased the threshold volume of colonic distension-induced abdominal withdrawal reflex in rats, suggesting CB could induce visceral antinociception. Pretreatment with either the CB1 or CB2 antagonist potently blocked the centrally injected orexin-A-induced antinociceptive action against colonic distension while CB2 but not CB1 antagonist blocked the brain ghrelin-induced visceral antinociception. These results suggest that the cannabinoid signaling may be involved in the central orexin- or ghrelin-induced antinociceptive action in a different mechanistic manner.